Although turbines are conventionally thought about as actuated by the reaction or impulse or both of a current of fluid subject to pressure, implying relatively high-volume, high-velocity, relatively low-pressure fluid, motor means having characteristics of a turbine but in a sense a hybrid with one or more expansion chambers actuated by low volume, low-velocity, high pressure fluid may also fill a useful set of functions in specialized applications. I have disclosed a suitable reciprocating power source supplying at very high pressure a low-velocity low volume flow and using at least in part relatively unexploited naturally-occuring sources of energy.